Abstract: In certain embodiments, for a blockchain such as the Ethereum blockchain, a data-processing engine maintains an accounts database having bloom filters that identify accounts that might have data in different portions of the blockchain, a blocks database that stores optimized versions of one or more (and possibly all of) the blocks in the blockchain, and a transaction-location database that stores a list of transaction locations for each of one or more accounts of interest (AOIs) supported by the engine. The engine uses the accounts and blocks databases to perform system-wide analyses quickly. The engine uses the transaction-location and blocks databases to generate reports for the AOIs quickly. The engine uses the accounts and blocks databases to generate, for the transaction-location database, a new transaction-location list for a new AOI quickly and without requiring a lot of memory.